Hello student,
A line makes an angle of

/4 with thepositivedirections of each of x- axis and y- axis therefore

,

We know that cos
2
+cos
2
+cos
2
=1
substituting the values of

in above equation we get

=90
Hence the line makes an angle of 90 with z axis
Thanks and Regards
Shaik Aasif
askIITians faculty